steam generating apparatus



Nov. 22, 1955 M. H. KUHNER 2,724,370

STEAM GENERATING APPARATUS Filed June 5, 1952 INVENTOR Mnx H. KUHNERATTORNEY United States Patent Ofiice Patented Nov. 22, 1955 2,724,370STEAM GENERATING APPARATUS Application June 3, 1952, Serial No. 291,533

3 Claims. (Cl. 122-406) This invention relates to steam generatingapparatus and more particularly to apparatus for draining the condensatetrough in the steam-and'water drum of a boiler.

In the generation of steam his usual practice to provide means forpurifying the steam before passing it intothe superheater. For thatpurpose certain steam treating apparatus has been placed in the path ofthe steam as it passes through the steam-and-water drum. One of theprincipal pieces of apparatus for this purpose is the condenser, aneffective type of which is shown in the patent to Andrews 2,424,212issued July 22, 1947. It has been proposed that this condenser be placedin a trough at one side of the drum, so that the boiler water will beexcluded therefrom and so that variation in water level during changesin load will not produce a change in the effective area of the condenserdue to the condenser being emersed in varying levels of water, However,one difiiculty encountered in the use of such a trough is that thecondensate from the condensers and also from other apparatus such asdrier cartons collects in the trough and may accumulate sufiiciently tocover the condensers and thus inhibit their action. The presentinvention obviates this difficulty in a novel and practical manner.

It is therefore an outstanding object of the present invention toprovide, an efiective means for draining condensate from a troughunderlying condensers in a steam boiler.

It is a further object of the invention to provide an apparatus fordraining the condensate trough of a steamand-water drum which apparatusmakes use of the natural circulation of the boiler.

Another object of this invention is the provision of drainage apparatusfor use in connection with drum internals which apparatus has a positiveaction, the activity of which changeswith fluctuation of the load on theboiler.

A still further object of the invention is the provision of a drainageapparatus for drum internals which is simple in construction and whichwill not be rendered ineffective by chemical deposits, extremetemperatures, and the like.

With the above objects in view, as well as others which will appear asthe specification proceeds, the invention comprises the construction,arrangement and combination of parts as now to be fully described and ashereinafter to be specifically claimed, it being understood that thedisclosure herein is merely illustrative and intended in no way in alimiting sense, changes in details of construction and arrangement ofparts being permissible within the spirit of the invention and the scopeof the claims which follow.

The character of the invention, however, may be best understood byreference to certain of its structural forms, as illustrated by theaccompanying drawings in which:

Figure 1 is a longitudinal sectional view of a steamand-water drumembodying features of the present invention, and

Figure 2 is a transverse sectional view of a drum embodying theinvention, the section being taken on the a line 22 of Figure l andsomewhat enlarged.

Referring first to Figure 1, wherein is best shown the general featuresof the invention, the steam-and-water drum, generally designated by thereference numeral 10, is shown as comprising an elongated tubularsection 11 closed at the ends by semi-spherical end members 12 havingmanholes 13 therein sealed by suitable closures 14. Extendinglongitudinally of the drum for most of its length is a trough 15 havingend walls 16. The trough defines an upwardly-opening enclosure, theopening of which is well above the maximum level of the boiler water. Atthe ends of the drum are situated downcomer tubes 17. The tubes are ofthe large type used in high-temperature boilers wherein no heat isabsorbed by the downcomers and a minimum number of very large tubesextend from the steam-and-water drum to the lower header or drum, thesetubes usually not forming part of the heat-absorbing surface. A drainageconduit 18 enters each end of the trough 15 in the lower portion thereofand extends outwardly and downwardly therefrom. Each conduit 18 ,entersits respective downcomer tube 17 and extends downwardly andconcentrically therein. The conduits 18 are somewhat smaller than thetubes 17 and, thus, an annular passage 19 is defined therebetweenthrough which the boiler water flows in its downward passage.

Referring next to Figure 2, which best shows the details of theinvention, it can be seen that a feedwater tube 20 enters the drum 10and is connected to a longitudinal header 21 which lies in the lowerportion of the trough 15. A series of condensers 22 extend upwardly fromthe header 21 in a generally vertical direction. The central tube 23 ofeach condenser bends downwardly and its end is situated under theminimum water level of the drum. A series of steam-release tubes 24 isarranged around the drum, while steam tubes 25 are connected to the drumin its upper portion and lead to the superheater, not shown. Adownwardly-depending separating wall 26 extends from the wall of thedrum adjacent the steam tubes 25 and defines, with thelupper portion ofthe trough 15, a passage 27. A series of drier cartons 28 is supportedin the space betweenthe wall of the drum and the separating wall 26. Inthis view and in Figure 1, it can be observed that the drainage conduit18 extends downwardly through the downcomer tube 17 to a point below thetransition portion where the tube is bent to carry it away from the heatabsorption portion of the furnace; this means that the lower end of thedrainage tube resides in a straight portion of the downcomer tube. Thedowncomer tube enters the drum radially and the entrance from the druminto the tube is the same size as the bore of the tube. In the annularspace between the entrance and the drainage conduit 18 is inserted avortex eliminator 30 which consists of at least one tube mountedconcentrically of the drainage conduit.

The operation of the apparatus will now be evident from the abovedescription. Feed water enters the system through the tube 20 and fillsthe header 21. From the header 21 the water flows upwardly through thecondenser 22, absorbing heat from the extended surface thereof and thenpasses downwardly into the lower portion of the drum through the centraltube 23. The water passes from the lower part of the drum through theentrance 29 into the downcomer tube 17, passing through the annularpassage 19 between the tube and the drainage conduit. While passingthrough the heat absorbing surfaces of the boiler, the water isconverted to steam and the steam enters the drum 10 through thesteam-release tubes 24. The steam passes upwardly and enters the passage27 between the separating wall 26 and the upper portion of the trough15. It then passes over the condensers 22 where a portion is condensedand most of the impurities are removed; the condensate. sirens into thelower nor-- tion of the trough 15. The .stearn then passes upwardlythrough the drier cartons 28 on the other side of the separating wall26, llhCuCfi-HOHS removing droplets en-. trained in flow. Dropletscollected by the cartons drop downwardly into .the trough also. It isnecessary to remove the condensate from the trough 15 more rapidly thanwould be possible by natural flow through the drainage conduits 18; thisis done by use of the aspirator effect of the flowof the boiler water inthe downcomer tube past the open lower end of the drainage conduit. Theflow .of water from the drum into the .downcomer tube is restricted :toa more or less linear flow by the vortex eliminator .30. Suchstraightfline flow will produce the optimum suction on the drainage tubeand will prevent other troubles that may arise because of the swirlingthat would otherwise be present.

The invention having been thus described, what is claimed as new anddesired to secure by Letters Patent is:

l. A steam generati-ngapparatus, comprising: a steam andr-water drum, aseries of condensers for treating steam passing thereover, saidcondensers extending vertically within the range of possible levels ofthe water in the drunna trough underlying and partially surrounding thesaid series, a downcomer tube connected to the lower portion of .saiddrum, a drainage conduit connected to the lower portion of said troughand entering the downcomer tube substantially coaxially therewith, and avortex eliminator situated in the entrance of the downcomer tube intothe drum, the vortex eliminator consisting of at least one tubularmember supported coaxially with the rainage conduit.

2. A steam generating apparatus, comprising: an elongated, tubularsteam=and-water drum, steam-release tubes entering said drum, steamtubes leaving said drum, a series of steam treating condensers lying inthe path of the steam as it proceeds from the steam-release tubes to thesteam tubes, the condensers being of tubular construction to carryincoming feed water internally thereof for the indirect condensation ofsteam on the exterior thereof, the Condensers having extended exteriorsurfaces, said condensers extending vertically within the range ofpossible levels of the water in the drum, a trough extendinglongitudinally of the drum and underlying the said series water level inthe drum, .a downcomer tube connected radially to the lower portion ofsaid drum, a drainage conduit connected to the lower portion of saidtrough and extending into the downcomer tube a considerable distancecoaxially therewith, and a vortex eliminator situated in the entrance ofthe downcomer tube.

3. A steam generating apparatus, comprising: an elongated, tubularsteam-and-water drum, steam-release tubes entering said drum, steamtubes leaving said drum, a series of vertical steam-treating condensersaligned side by side longitudinally of the drum lying in the path of thesteam as it proceeds transversely of the drum from the steamreleasetubes to the steam tubes, the condensers being of tubular constructionto carry incoming feed water intersaid series 10 a height well above themaximum possible nally thereof for the indirect condensation of steam onthe exterior thereof, the condensers having extended exterior surfaces,said condensers extending vertically within the range of possible levelsof the water in the drum, a trough extending longitudinally of the drum,and underlying the said series of condensers, the trough extendingupwardly around the said series to a height well above the possiblewaterlevel in the drum, a downcorner tube connected radially to thelower portion of said drum, a drainage conduit connected to the'lowerportion of said trough extending into the downcomer tube a considerabledistance coaxially therewith, and a vortex eliminator consisting of atleast one tubular member situated in the entrance of the downcomer tube,said eliminator being supported coaxially of the said tube.

' Refer nces C te the fil of this patent UNITED STATES PATENTS,

OTHER REFERENCE Riley Condenser Steam Power Purifier, Sept. 1950.

